[netcdf-java] I/O perfomance

• To: "netcdf-java@xxxxxxxxxxxxxxxx" <netcdf-java@xxxxxxxxxxxxxxxx>
• Subject: [netcdf-java] I/O perfomance
• From: Antonio Rodriges <antonio.rrz@xxxxxxxxx>
• Date: Wed, 21 Sep 2016 23:07:29 +0300

Hello,

I have written a simple test that opens NetCDF3 file (50.2 MB), reads its
whole array time x lat x lon = 1460 x 94 x 192

Open file: 838 ms
Find var: 12 ms
Read array: 2393 ms
(code is below)

Numbers are for SSD with approx 222 MB/sec speed

This is almost 3 sec while during the same time C++ code (NCO, CDO) may do
a lot more.

My questions are:
- could this be improved? (e.g. link to native lib or smth else)
- is this the fastest way to read array (code below)?

Thanks

        long millis = System.currentTimeMillis();

        NetcdfFile FILE = NetcdfFile.open(filepath, null);
        System.out.println("Open file: " + (System.currentTimeMillis() -
millis));

        millis = System.currentTimeMillis();
        Variable var = FILE.findVariable("uwnd");
        System.out.println("Find var: " + (System.currentTimeMillis() -
millis));

        int[] origin ;
        int[] shape ;

        millis = System.currentTimeMillis();
        shape = var.getShape();
        System.out.println("Get shape: " + (System.currentTimeMillis() -
millis));

        origin = new int[shape.length];

        millis = System.currentTimeMillis();
        Array values = var.read(origin, shape);
        System.out.println("Read array: " + (System.currentTimeMillis() -
millis));

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  • Re: [netcdf-java] I/O perfomance
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